Wasser in der Landwirtschaft - agriwaterpedia.info

In seasonal wetlands and floodplains, trap ponds are a traditional form of harvesting fish, and also for
farmers to take initial steps into cultivation such as through protection, feeding, prolonging the water in
the pond for better growth and better market prices.
Community-based fish culture in fenced-off areas during the flood season has been proven to be a
successful technology and is spreading in Bangladesh and northern Vietnam. Initial trials have led to yields
of over US$1000/ha per year as compared to previous management systems. Sharing arrangements
between landowners and landless achieved income increases for the landless from initially 260 to 480
US$/ha. The landless poor continued to have access to the small indigenous fish which they caught and
played an important role for household income and nutrition during the flood season. Likewise,
biodiversity in the floodplains was not affected from the stocking of omnivorous (non-predatory) fish for
culture.
Numerous examples exist for wastewater fed aquaculture; today the larger operations in Kolkata, Hanoi
and Munich are noteworthy. Small scale reuse of nightsoil directly into fish ponds has been increasingly
discouraged or even prohibited due to health reasons, but is still a widespread activity in parts of Asia.
In canals and irrigation waterways, numerous forms of aquaculture as well as capture fisheries are conducted,
but are influenced by the flow management regime of the canals.
A3.9 Ecosan Projects and Agriculture – Showing the Potential of Reuse Oriented Sanitation
Systems for Improving Food Security
Elisabeth von Münch und Sören Rüd
GTZ, Kompetenzfeld Wasser, OE 4412
The concept of food security has been on the international agenda since the Human Rights Declaration in
1948 and was seen by many as one of the fundamental rights of human beings. Currently some estimated
854 million people worldwide are chronically hungry due to extreme poverty. Considering the continuous
growth of the world population the problem of food insecurity will probably worsen in the coming
decades. A great deal of this population growth will take place in cities with a substantial increase in the volume
of urban wastewater, an over-exploitation of resources and a significant increase in urban food demand.
The most important nutrients that leave the fields through harvest are partly compensated by inorganic
fertilizers, but these are often not affordable for poorer segments of the population. As a result soil
fertility is declining, particularly in many regions of Sub-Saharan Africa.
A further problem is that phosphorus is a non-renewable resource. It has been estimated that the global
production peak for P was already reached in the late 1990s and that global rock phosphorus-reserves will
only last for the next 50 to 100 years. Coupled with an increasing water and food demand of the growing
human population, a new approach that recognises human excreta and wastewater load as an important
resource for nutrients and agricultural irrigation is imperatively necessary.
The reuse of valuable resources like treated wastewater, urine or dried faeces together with animal manure
and organic solid waste can partly or completely substitute the use of synthetic fertilisers or freshwater
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